[p53 expression in the gastric mucosa of patients infected with Helicobacter pylori]. / p53 expresado en la mucosa gástrica de pacientes infectados por Helicobacter pylori.

BACKGROUND: Helicobacter pylori (Hp) is recognized as a type 1 carcinogen for gastric cancer associated with pre-neoplastic lesions (atrophy and intestinal metaplasia [IM]). Its relation with p53, which intervenes in the cell cycle, has had contradictory results. AIMS: To analyze p53 expression in gastric mucosa and its relation with Hp infection. METHODS: A 3-month prospective, observational, cross-sectional study was conducted. Patients that had no evidence of acute or clinically significant gastric pathology had biopsies taken according to the Sydney system at the Hospital Juárez de México and the histopathologic studies were done at the Hospital Español de México. RESULTS: Hp prevalence was 32.7% in 104 patients. There were no cases of atrophy or dysplasia. A total of 91% of the infected patients were positive for p53. Of the non-infected patients, 14% were positive for p53 and 60% of them had IM. Of the IM patients, 75% presented with positive p53. Of the patients without IM, 31 presented with positive p53, and Hp was positive in 85% of them. There was association between Hp and p53 and between p53 and IM (P<.0001 and P<.0006, respectively). CONCLUSIONS: Significant association was shown between Hp and p53 expression, even in patients with pre-neoplastic lesions that no longer presented with Hp. Given that the identification of pre-neoplastic lesions is important for the prevention of cancer, immunohistochemistry could benefit routine biopsy carried out during endoscopy for the detection of Hp, by identifying patients with expression of the important oncogene regulator, p53.

Simplified magnetic anchor-guided endoscopic submucosal dissection: an ex vivo porcine model.

INTRODUCTION AND AIMS: Endoscopic submucosal dissection (ESD) is a well-established treatment for superficial gastrointestinal tumors and enables en bloc resection. Adequate tissue tension is important for safe and effective dissection. Simplified magnetic anchor-guided ESD (MAG-ESD) with a neodymium magnet has potential benefits, compared with other current traction methods. We evaluated the feasibility of simplified MAG-ESD in an ex vivo porcine model. MATERIALS AND METHODS: An experimental study was conducted, utilizing the standard ESD technique. An external magnet and an internal magnet, both neodymium magnets, were used for the magnetic anchoring. The internal magnet was attached to an arm of a hemoclip with a 2-0 silk suture. After the incision, the clip with the internal magnet was placed at the edge of the lesion. The external magnet was maneuvered around the surface to apply adequate tension. RESULTS: A total of 15 en bloc ESDs (5 with no magnetic anchoring and 10 with magnetic anchoring) were carried out. Traction and dissection were feasible in all cases and the procedures were completed in fewer than 90min. Lesion size ranged from 15 to 50mm (mean 30mm). Two cases in the group with magnetic anchoring presented with punctate perforation (13.3%). CONCLUSIONS: Our study demonstrated the feasibility of simplified MAG-ESD and en bloc resection in an ex vivo porcine model.

Simplified magnetic anchor-guided endoscopic submucosal dissection: an ex vivo porcine model. / Disección endoscópica de la submucosa asistida con anclaje magnético simplificado: modelo porcino ex vivo.

INTRODUCTION AND AIMS: Endoscopic submucosal dissection (ESD) is a well-established treatment for superficial gastrointestinal tumors and enables en bloc resection. Adequate tissue tension is important for safe and effective dissection. Simplified magnetic anchor-guided ESD (MAG-ESD) with a neodymium magnet has potential benefits, compared with other current traction methods. We evaluated the feasibility of simplified MAG-ESD in an ex vivo porcine model. MATERIALS AND METHODS: An experimental study was conducted, utilizing the standard ESD technique. An external magnet and an internal magnet, both neodymium magnets, were used for the magnetic anchoring. The internal magnet was attached to an arm of a hemoclip with a 2-0 silk suture. After the incision, the clip with the internal magnet was placed at the edge of the lesion. The external magnet was maneuvered around the surface to apply adequate tension. RESULTS: A total of 15 en bloc ESDs (five with no magnetic anchoring and 10 with magnetic anchoring) were carried out. Traction and dissection were feasible in all cases and the procedures were completed in fewer than 90 min. Lesion size ranged from 15 to 50 mm (mean 30 mm). Two cases in the group with magnetic anchoring presented with punctate perforation (13.3%). CONCLUSIONS: Our study demonstrated the feasibility of simplified MAG-ESD and en bloc resection in an ex vivo porcine model.